Human heart valves under the conditions of normal physiological functions are passive devices that open under the pressure of blood flow on their leaflets. Four valves in the heart serve to direct the flow of blood through all chambers in a forward direction. In addition to the four heart valves (tricuspid valve, mitral valve, aortic valve, and pulmonary valve), a patient has other flow-regulatory valves, such as venous valves, sphincter valves, and the like.
When disease conditions affect the structure or the materials of the native valve, the valve itself will decay, degenerate or disrupt and require repair or replacement to restore proper function necessary for the continuation of life.
U.S. Pat. No. 4,451,936 to Carpentier et al., entire contents of which are incorporated herein by reference, discloses an aortic prosthetic valve for supra-annular implantation comprising a valve body of generally annular configuration and a valve element movably mounted on the valve body for opening and closing the valve, and a scalloped suture ring circumscribing the valve body adjacent the base surface and configured to approximately fit the contour of the Sinuses of Valsalva at the base of the aorta.
U.S. Pat. No. 4,790,843 to Carpentier et al., entire contents of which are incorporated herein by reference, discloses a prosthetic heart valve assembly that includes an artificial annulus, a prosthetic valve and a retaining ring for releasably retaining the prosthetic valve on the artificial annulus. By removing the retaining ring, the valve can be replaced with another valve.
U.S. Pat. No. 4,994,077 to Gabbay, entire contents of which are incorporated herein by reference, discloses an improved prosthetic heart valve comprising a support body or stent covered by a layer of biological tissue having only the smooth surfaces thereof presented outwardly. The valve cusp is made of pericardial tissue that has been doubled over such that the rough side thereof is folded inwardly.
U.S. Pat. No. 4,994,077 to Dobben, entire contents of which are incorporated herein by reference, discloses a valve system consisting of a cylindrical or crown shaped stent that is made by bending wire into a zigzag shape to anchor the device and attach the flow regulator flap of a valve. The device presents significant hemodynamic, delivery, fatigue and stability disadvantages.
U.S. Pat. No. 5,163,953 to Vince, entire contents of which are incorporated herein by reference, discloses a valve system consisting of a flow-regulation mechanism of a flap of biologic material that is mounted inside a stent comprised of a toroidal body formed of a flexible coil of wire. The main shortcoming of this design is the profile and configuration, thus making the device clinically ineffective as a minimally invasive technique.
U.S. Pat. No. 5,332,402 to Teitelbaum, entire contents of which are incorporated herein by reference, discloses a valve system consisting of shape memory Nitinol and a flow-regulating valve. The stent-like support is comprised of a meshwork or braiding of Nitinol wire with trumpet-like distal and proximal flares. The flared ends are intended to maintain the position of the stent component across the valve thereby anchoring the device. The disadvantages of the device are the reduced valve orifice and sub-optimal hemodynamic characteristics.
U.S. Pat. No. 5,370,685 to Stevens, entire contents of which are incorporated herein by reference, discloses a percutaneous valve replacement system for the endovascular removal of a malfunctioning valve followed by replacement with a prosthetic valve. The valve replacement system may include a prosthetic valve device comprised of a stent and cusps for flow-regulation such as a fixed porcine aortic valve, a valve introducer, an intraluminal procedure device, a procedure device capsule and a tissue cutter. The valve device disclosed requires a large delivery catheter and intraluminal-securing means such as suturing to anchor the device at the desired location.
U.S. Pat. No. 5,397,351 to Pavcnik et al., entire contents of which are incorporated herein by reference, discloses a self-expanding percutaneous valve comprised of a poppet, a stent and a restraining element. The valve stent has barbed means to anchor to the internal passageway. The device includes a self-expanding stent of a zigzag configuration in conjunction with a cage mechanism comprised of a multiplicity of crisscrossed wires and a valve seat. The disadvantages of the device include large delivery profile, reduced effective valvular orifice, and possible perivalvular leakage.
U.S. Pat. No. 5,411,552 to Andersen et al., entire contents of which are incorporated herein by reference, discloses various balloon expandable percutaneous prosthetic valves. One embodiment discloses a valve prosthesis comprised of a stent made from an expandable cylindrical structure and an elastically collapsible valve mounted to the stent. The device is placed at the desired location by balloon expanding the stent and the valve. The main disadvantage to this design is the 20+ French size delivery catheters.
U.S. Pat. No. 5,445,626 to Gigante, entire contents of which are incorporated herein by reference, discloses a valve operated catheter for urinary incontinence and retention comprising a flexible duct designed to be inserted in the patient's urethra, the catheter provided with a spiral shaped end portion, having a plurality of holes for the passage of urine. The duct is provided, at its other end, with a seat in which there is housed a valve made of elastic material, the valve being usually closed because of the elastic action.
U.S. Pat. No. 5,500,014 to Quijano et al., entire contents of which are incorporated herein by reference, discloses a biological valvular prosthesis comprising a chemically fixed conduit derived from a harvested vein segment bearing at least one integrally formed venous valve, and a restriction means positioned about the conduit at either side of the venous for restricting the venous valve from expanding outwardly.
U.S. Pat. No. 5,824,064 to Taheri, entire contents of which are incorporated herein by reference, discloses an aortic valve replacement system combined with an aortic arch graft. The devices and percutaneous methods described require puncture of the chest cavity.
U.S. Pat. No. 5,855,597 to Jayaraman, entire contents of which are incorporated herein by reference, discloses a device comprising a star-shaped stent, a replacement valve and a replacement graft for use in repairing a damaged cardiac valve. The device is comprised of a chain of interconnected star-shaped stent segments in the center of which sits a replacement valve. The flow-regulation mechanism consists of three flaps cut into a flat piece of graft material that is rolled to form a conduit in which the three flaps may be folded inwardly in an overlapping manner.
U.S. Pat. No. 5,855,601 to Bessler et al., entire contents of which are incorporated herein by reference, discloses methods and devices for the endovascular removal of a defective heart valve and the replacement with a percutaneous cardiac valve. The device is comprised of a self-expanding stent member with a flexible valve disposed within. The stent member is of a self-expanding cylindrical shape made from a closed wire in a zigzag configuration that can be a single piece, stamped, extruded or formed by welding the free ends together. The flow-regulation mechanism is comprised of an arcuate portion that contains a slit to form leaflets and a cuff portion that is sutured to the stent and encloses the stent. The preferred flow regulator is a porcine pericardium with three cusps.
U.S. Pat. No. 5,925,063 to Khosravi, entire contents of which are incorporated herein by reference, discloses a percutaneous prosthetic valve comprised of a coiled sheet stent to which a plurality of flaps are mounted on the interior surface to form a flow-regulation mechanism that may be comprised of a biocompatible material. The disadvantages of this design include problematic interactions between the stent and flaps in the delivery state, and the lack of a detailed mechanism to ensure that the flaps will create a competent one-directional valve.
U.S. Pat. No. 5,954,766 to Zadano-Azizi et al., entire contents of which are incorporated herein by reference, discloses a device in which flow-regulation is provided by a flap disposed within a frame structure capable of taking an insertion state and an expanded state. The preferred embodiment of the flow-regulation mechanism is defined by a longitudinal valve body made of a sufficiently resilient material with a slit that extends longitudinally through the valve body.
U.S. Pat. No. 5,957,949 to Leonhardt et al., entire contents of which are incorporated herein by reference, discloses a prosthetic valve comprised of a tubular graft having radially compressible annular spring portions and a flow regulator, which is preferably a biological valve disposed within. In addition to oversizing the spring stent by 30%, anchoring means is provided by a light-activated biocompatible tissue adhesive that is located on the outside of the tubular graft and seals to the living tissue. Disadvantages of this device include those profile concerns, a large diameter complex delivery system, and feasibility of the light actuated anchoring means.
U.S. Pat. No. 6,106,550 to Magovern et al., entire contents of which are incorporated herein by reference, discloses an implantable apparatus for receiving a heart valve, comprising an annular ring having an inner wall and an outer wall, a plurality of channels displaced circumferentially about the ring, each channel extending from the inner wall to the outer wall, and a plurality of tissue attachment pins each pin being movable in a respective one of the channels between a first position during implantation, and a second position wherein the first end of each pin extends beyond the outer wall for tissue attachment.
U.S. Pat. No. 6,168,614 to Andersen et al., entire contents of which are incorporated herein by reference, discloses a method of endovascularly delivering a valve through a blood vessel, comprising the steps of providing a tissue valve and an expandable support structure, connecting the tissue valve to the support structure, and securing the tissue valve and the support structure to a desired valve location with the support structure in the expanded shape.
U.S. Pat. No. 6,206,911 to Milo, entire contents of which are incorporated herein by reference, discloses an expandable stent that is created so as to undergo essentially no axial foreshortening when expanded from an unexpanded or compressed configuration to an operative configuration. Attachment to the surrounding tissue may be via pairs of needle-like projections or prongs that may be bent to have a radial orientation during the deployment phase.
U.S. Pat. No. 6,283,127 to Sterman et al., entire contents of which are incorporated herein by reference, discloses a device system and methods facilitating intervention within the heart or a great vessel without the need for a median sternotomy or other form of gross thoracotomy, substantially reducing trauma, risk of complication, recovery time, and pain for the patient. Using the device systems and methods of the invention, surgical procedures may be performed through percutaneous penetrations within intercostal spaces of the patient's rib cage, without cutting, removing, or significantly displacing any of the patient's ribs or sternum.
U.S. Pat. No. 6,530,952 to Vesely, entire contents of which are incorporated herein by reference, discloses a cardiovascular valve system including a permanent base unit that is affixed to the patient using conventional sutures or staples, and a collapsible valve having a collapsible frame that mates with the permanent base unit, and supports valve leaflets. An installed collapsible frame may be re-collapsed and disengaged from the permanent housing whereas a new collapsible valve is then installed, to resume the function of the prosthesis.
U.S. Pat. No. 6,582,462 to Andersen et al., entire contents of which are incorporated herein by reference, discloses a valve prosthesis for implantation in a body channel by way of catheterization, the prosthesis comprising a radially collapsible and expandable cylindrical stent and a collapsible and expandable valve having commissural points wherein the valve is mounted to the stent at the commissural points.
U.S. Pat. No. 6,569,196 to Vesely, entire contents of which are incorporated herein by reference, discloses a system for minimally invasive insertion of a bioprosthetic heart valve. The system includes a collapsible tissue-based valve system, a catheter-based valve delivery system, a surgical platform and a device tracking and visualization system, wherein the collapsible valve system includes a permanent outer frame that is affixed to the patient using conventional sutures or staples and a collapsible valve having a collapsible inner frame that mates with the outer frame.
U.S. Pat. No. 6,652,578 to Bailey et al., entire contents of which are incorporated herein by reference, discloses a catheter system with minimally invasive techniques for percutaneous and transluminal valvuloplasty and prosthetic valve implantation.
U.S. Pat. No. 6,830,584 to Seguin, entire contents of which are incorporated herein by reference, discloses a device for replacing, via a percutaneous route, a heart valve located in a bodily vessel, comprising an elongated support element, two series of elongated blades arranged around the circumference of the elongated elements, where the blades have opposite cutting edges and can be extended corolla-shaped such that their cutting edges are set in the extension of one another thereby forming circular cutting edges to cut the native valve so as to separate it from the corporeal duct.
U.S. Pat. No. 6,830,585 to Art of et al., entire contents of which are incorporated herein by reference, discloses a percutaneously deliverable heart valve with a plurality of valvular leaflets, the plurality of leaflets being sewn together at least a potion of their side edges to form an annulus at about the in-flow edge and a plurality of commissure tissues.
U.S. Pat. No. 6,896,690 to Lambrecht et al., entire contents of which are incorporated herein by reference, discloses a device for performing intravascular procedures wherein at least a portion of the device is configured for placement in a flowpath of a blood vessel. The device comprises a valve means configured to allow greater antegrade flow than retrograde flow through the vessel and a filter operative to restrict the passage of emboli while allowing blood flow through the vessel.
U.S. Pat. No. 6,908,481 to Cribier, entire contents of which are incorporated herein by reference, discloses a valve prosthesis comprising a collapsible, elastic valve member, an elastic stent member in which the valve member is mounted, and a support coupled to the valve member and positioned between the valve member and the stent member, wherein the stent member forms a continuous surface and comprises strut members that provide a structure sufficiently rigid to prevent eversion.
U.S. Pat. No. 6,951,571 to Srivastava, entire contents of which are incorporated herein by reference, discloses a valve-implanting device comprising a collapsible frame, inner and outer guide wires removably connected to the collapsible frame, and a plurality of valve flaps attached to the collapsible frame.
U.S. Pat. No. 6,974,476 to McGuckin, Jr. et al., entire contents of which are incorporated herein by reference, discloses a valve system comprising a first substantially annular portion adapted to be positioned on a proximal side of the annulus of a patient and a second substantially annular portion adapted to be positioned on a distal side of the annulus of a patient, wherein at least one of the first and second substantially annular portions is movable towards the other portion to a clamped position to clamp around the annulus. The second portion has a flow restricting apparatus.
Each of the prior art stent valve designs has certain disadvantages which are resolved by the present embodiments. The prior art valve prosthesis generally consists of a support structure with a tissue valve connected to it, wherein the support structure is delivered in a collapsed shape intraluminally and secured to a desired valve location with the support structure in the expanded shape. However, the support structure tends to compressively impinge a portion of the leaflets of the tissue valve at the structure struts when the support structure is expanded by an inflatable balloon for positioning endovascularly. The impinged leaflets tend to deteriorate and calcify, making the valve useless.